The mammalian ear has an extraordinary capacity to detect very low-level acoustic signals from the environment. Sound pressures as low as a few μPa (？10？dB SPL) can activate cochlear hair cells. To achieve this sensitivity, biological noise has to be minimized including that generated by cardiovascular pulsation. Generally, cardiac pressure changes are transmitted to most peripheral capillary beds; however, such signals within the stria vascularis of the cochlea would be highly disruptive. Not least, it would result in a constant auditory sensation of heartbeat. We investigate special adaptations in cochlear vasculature that serve to attenuate cardiac pulse signals. We describe the structure of tortuous arterioles that feed stria vascularis as seen in corrosion casts of the cochlea. We provide a mathematical model to explain the role of this unique vascular anatomy in dampening pulsatile blood flow to the stria vascularis. 1. Introduction Without a stethoscope, we do not normally hear our own heart beat, although there are some pathological conditions when it can be heard (e.g., high blood pressure, pulsatile tinnitus, and superior semicircular canal dehiscence). In these cases, the perceived heart sound is usually the result of signals from arteries external to the cochlea rather than pressure changes generated within cochlear vessels. The energy requirements of the cochlea are high, in particular the for Na/K ion exchange pumps that generate the endolymphatic potential. A good vascular supply is essential but mechanical stimulation has to be minimized. The cochlea appears to have a unique blood supply vasculature that ensures a dampening of cardiovascular pressure changes, essentially converting a pulsatile flow to a more linear stream. The requirement for this damping mechanism is obvious given the sensitivity of cochlear hair cells to detect mechanical signals. The most direct blood supply to the organ of Corti is sparse, typically a small arteriole running adjacent to the basilar membrane. This may be one adaptation to keep pulsating vessels away from hair cells. On the other hand, the dense capillary network of the stria vascularis is richly supplied, and it is these feeding vessels that are described and modeled in the present study. In many peripheral capillary beds (e.g., skin, lips, and retina), cardiovascular pulsation can be measured [1–3]. Blood pressures changes of up to 12？mmHg have been measured in the skin of healthy human adults [4]. This degree of pulsation in vessels of the stria vascularis would be highly disruptive to cochlear
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